"The mouth is an open wound," sings Kelli Schaefer on her new EP, and the 28-year-old Portland enchantress lets hers bleed all over these four spectral songs. On 601, Schaefer's already unadorned songwriting gets stripped to the bone. Ghost of the Beast, her 2011 full-length, folded white noise and ambient sounds into the crooks of her sometimes raging, sometimes fragile indie-folk. Now, she's writing whole songs out of those bits of ephemera. Bells, shakers, one-note bass pulses and what sounds like steam valves are her prime accompaniment; the drums and guitars are just streaks in the atmosphere.

Within such minimalism, it's important that Schaefer maintain a presence. She isn't a showy singer, but she is a dynamic one, and her ability to put every range-stretching howl and half-muttered warble in its precise place makes the tracks on 601 at once confessional and hauntingly ambiguous. "When I don't have anything good to say/ I open my mouth anyway," she confesses on "I'll Take You," a song about carrying someone away from the tyranny of their father, though it's never clear if she's addressing a friend, a lover or herself. "You better pull it together," she commands on "Calm Down," over trance-y, tribalist blues, but again, it could be her trying to shake someone else out of their complacency, or a moment of self-laceration.

And when Schaeffer does disappear, she's sure to make a point of it: On closer "Inside the House Where Nobody Lives," a nine-minute drift into tranquil ambience, Schaeffer's multitracked voice slowly evaporates, vanishing like dandelion spores in the wind. It's a brilliant cliffhanger: The intrigue is in seeing where it'll bloom next.

SEE IT: Kelli Schaefer plays Union Pine, 525 SE Pine St., with the Beauty and No More Train Ghosts, on Thursday, June 13. 6 pm. Free. All ages.